A superior form of solar radiation collection system is disclosed and claimed in U.S. Pat. No. 4,054,124, which discloses a dual flow path system of high efficiency, short time constant and high effectiveness in suppressing free convection losses. The present invention is particularly well adapted for usage with the dual flow concept, but in addition is of general applicability to solar radiation collection systems of all kinds.
Most workers in the prior art have fabricated relatively large collector panels, typically of rectangular configuration and with widths of 1 to 2 meters and lengths of 1.5 to 2.5 meters and more. A film of air is then swept along the collector surface that is to be heated, which is typically a high conductivity sheet supported at its edges in a frame, along with a transparent cover and a rearwardly mounted insulative structure behind the panel. Usually water or other liquid is passed in heat exchange relation with the panel so that both the panel and the liquid conduit system are relatively heavy and a suitably rugged frame must be used. Above referenced U.S. Pat. No. 4,054,124 teaches a high efficiency system in which air or other gas may be used by, among other things, providing a thin sheet-like flow of gas beneath a thin planar collector. When fabrication problems, efficiency limitations and usage factors are considered in detail in this context, moreover, the basic configuration of a frame supported system has significant additional deficiencies. For example, a large aluminum panel that is adequately thin to be inexpensive is not physically self-supporting, and is so fragile as to be readily damaged during or after installation. Furthermore, such a large panel undergoes significant temperature expansion, and this must be accounted for unless buckling of the panel is to be accepted along with the consequent loss of efficiency. Furthermore, the weight and cost of the glass utilized in such a panel are substantial parts of the weight and cost of the overall device. It is also difficult to arrange a set of large panels into a suitable array so as to provide the heating capabilities needed for large installations.